Cycling regimen induces spinal circuitry plasticity and improves leg muscle coordination in individuals with spinocerebellar ataxia

Objectives To compare the reciprocal control of agonist and antagonist muscles in individuals with and without spinocerebellar ataxia (SCA) and to evaluate the effect of a 4-week leg cycling regimen on functional coordination and reciprocal control of agonist and antagonist muscles in patients with SCA. Design Randomized controlled trial with repeated measures. Setting Research laboratory in a general hospital. Participants Individuals with SCA (n=20) and without SCA (n=20). Interventions A single 15-minute session of leg cycling and a 4-week cycling regimen. Main Outcome Measures Individuals with SCA (n=20) and without SCA (n=20) underwent disynaptic reciprocal inhibition and D1 inhibition tests of the soleus muscles before and after a single 15-minute cycling session. Individuals with SCA were randomly assigned to either participate in 4 weeks of cycling training (n=10) or to receive no training (n=10). The disynaptic reciprocal inhibition and D1 inhibition and International Cooperative Ataxia Rating Scale (ICARS) scores were evaluated in both groups after 4 weeks. Results Individuals with SCA showed abnormally strong resting values of disynaptic reciprocal inhibition and D1 inhibition (P<.001) and impaired inhibition modulation capacity after a single 15-minute session of cycling (P<.001). The inhibition modulation capacity was restored (P<.001), and the ICARS scores improved significantly (pre: 13.5±9.81, post: 11.3±8.74; P=.046) after 4 weeks of cycling training. Conclusions A 4-week cycling regimen can normalize the modulation of reciprocal inhibition and functional performance in individuals with SCA. These findings are applicable to the coordination training of patients.